Disinherited Ancestor: Lucy’s kind may occupy evolutionary side branch

About 30 years ago, African excavations yielded the 3.2-million-year-old partial skeleton that became known as Lucy. The find, along with other fossils unearthed soon after, belongs to the species Australopithecus afarensis. Many scientists regard these creatures as ancestors of both the lineage that led to modern humans and of another, now-extinct evolutionary lineage known as robust australopithecines.